Antenna



FIG. 1 is a top plan view of an antenna;

FIG. 2 is a side elevation view thereof;

FIG. 3 is a side elevation view thereof;

FIG. 4 is a front elevation view thereof;

FIG. 5 is a rear elevation view thereof;

FIG. 6 is a top perspective view thereof; and,

FIG. 7 is a top perspective view thereof.

The broken line showing of a base represents unclaimed environment onlyand forms no part of the claimed design

CLAIM The ornamental design for an antenna, as shown and described.